The present invention relates generally to an improved metal cleaning composition, and more particularly to a formulation for preparing aqueous metal cleaning and polishing baths. The formulation is ecologically desirable, with a capability of effective use at relatively low temperatures, and furthermore is free of poly or orthophosphates which tend to require added effort during chemical effluent treatment.
The formulation of the present invention, in aqueous solution, is useful as a cleaner-degreaser for ferrous and non-ferrous metals. The formulation is ideally suited for cleaning metal surfaces, and is effective for the removal of oils, lubricants, rust preventatives, and other processing soils from the surfaces of metallic pieces or parts, such as steel, stainless steel, iron, aluminum, zinc, copper, brass and other ferrous and non-ferrous metals and alloys.
Metal surface cleaners and degreasers most commonly used are effective only when the operating temperatures are maintained above 65.degree. C., and frequently require working solution temperatures in the range of 80.degree. C. - 95.degree. C. Furthermore, the metal cleaner-degreasers in common use at this time require high concentrations in the working solutions in order to effect thorough cleaning and saponification of fatty acid soils or otherwise form stable emulsions. The utilization of these heavier concentrations, of course, provide additional energy requirements at chemical effluent treatment centers. Furthermore, if operating temperatures are lowered for conventional metallic cleaner-degreaser solutions, high foam formation normally occurs, thus rendering the materials unsuited for use at these lower temperatures.
As has been indicated, the wetting agents employed in the present formulation are biodegradable. The wetting agents have a predetermined and preselected range of cloud points, thus rendering the solutions active and highly effective at low temperatures. The metallic cleaner-degreasers of the present invention accomplish cleaning through solvation of viscous soils and ultimate displacement of fluidized soils from metallic surfaces, with physical or mechanical aids being utilized, including sprays, turbulation aids, air agitation, sonic or ultrasonic generators and the like. With such mechanical cleaning aids, it has been found that the formulation provides working solutions with desirable and effective foam height throughout the entire useful life of the working solution, with the foam height being maintained under a broad range of temperatures, including ambient to approximately 65.degree. C.